1. Field of the Invention
The present invention relates generally to extendable support members. More particularly, the present invention relates to an internal locking device for telescopic tube sections that provides secure locking and does not require a release mechanism to be extended.
2. Related Art
There are many types of support devices that utilize telescoping support legs, especially where the support devices are intended to be easily portable. Such support devices include tripods, tables, easels, etc. Likewise, there are many forms of locking devices for telescoping support legs for these devices. One such leg-locking mechanism is disclosed in U.S. Pat. No. 6,050,531, the disclosure of which is incorporated herein by reference in its entirety. Many such locking devices use clamp and bolt mechanisms, spring-loaded pins and holes, cam-lock devices, wing nut-operated clamps, threaded collar clamps, internal threaded studs, resilient washers, etc. Many of these require rotation of a collar or of an individual leg section in order to lock or un-lock it from a given position. Some of them do not allow adjustable extension of the legs, but allow fixation of a leg only in designated positions. Others require external protrusions and parts that can fall off and become lost.
Additionally, some telescoping tube leg-locking devices are cumbersome and time-consuming to use, requiring several complicated maneuvers to lock or unlock a leg segment. Some prior leg-locking devices also require telescoping leg sections of a particular cross-sectional shape. Moreover, some have locking mechanisms that can be relatively easily forced to move when in the locked position, thus producing extreme wear, and reducing the useful life of the device.